Manifold sensing device



Sept. 10, 1963 D. J. CAMERON 3,

MANIFOLD SENSING DEVICE Filed Oct. 9. 1961 u u z 56 I 55 INVENTOR.flan/1940 d (PINE/Po BY 60 W9 M United States Patent 3,103,211 MANIFOLDSENSING DEVMIE Donald .1. Cameron, Roseville, Mich assignor to HolleyCarburetor Company, Warren, Mich, a corporation of Michigan Filed Oct.9, 1961, Ser. No. 143,879 12 Claims. (Cl. 123-440) The present inventionrelates to fuel metering and pumping systems in conjunction withinternal combustion engines and the like and refers more specifically toan improved manifold sensing device for use with such systems includingmeans for compensating for erroneous engine manifold vacuum indicationsat idle speeds.

The recent trend in engine design has been toward engines of greatersize requiring greater air flows and having increased compressionratios. With such engines it has been found that in order to maintainthe higher compression ratios at higher speeds an increased valveoverlap, which may be defined as that number of engine degrees by whichthe opening and closing of the intake or exhaust valves of an internalcombustion engine overlap each other, is required.

However, it has been discovered that due to the increased valve overlapthe manifold vacuum existing at idle speeds is actually less than thetheoretical manifold vacuum because of exhaust gases escaping into theintake manifold. This phenomenon diminishes as the speed of the engineincreases. Accordingly if manifold vacuum is used as a parameter to themetering of fuel to the engine in accordance with the speed of theengine it will be apparent that if the fuel flow is adjusted so as to beproper for idle conditions that the fuel flow becomes excessively richfor subsequent speeds.

It is therefore an object of the present invention to provide improvedmeans for metering fuel to an internal combustion engine or similardevice in accordance with engine manifold vacuum.

Another object is to provide a manifold sensing device for use withinternal combustion engines or the like including means for compensatingfor the effect of valve overlap on manifold vacuum at idle speeds.

Another object is to provide pump means for pumping fuel to an internalcombustion engine or similar device, means for metering the amount offuel pumped in accordance with manifold vacuum and means to compensatethe manifold vacuum for the effect of valve overlap thereon at idlespeeds.

Another object is to provide means for pumping fuel to an internalcombustion engine, means for metering the fuel pumped to the engineincluding an adjustable abutment positionable to determine the quantityof fuel metered, a vacuum cylinder having a piston therein which pistonis actuated by manifold vacuum to adjust the abutment, and means forcompensating for the effect of valve overlap at engine idle speed on theposition of the piston comprising a cylinder within the first mentionedpiston, a piston within the last mentioned cylinder and means forconnecting the last mentioned cylinder to manifold vacuum at idlespeeds.

Another object is to provide a fuel pumping and metering system as setforth above wherein the vacuum applied to the last mentioned cylinder isvaried in accordance with the position of the speed control member ofthe engine.

Another object is to provide a fuel pumping and metering system as setforth above including means for adjusting the manifold vacuum applied tothe last mentioned cylinder at idle engine speed.

Another object is to provide a manifold sensing device which is simplein construction, economical to manufacture and efficient in use.

ice

Other objects and features of the invention will become apparent as thedescription proceeds, especially when talcen in conjunction with theaccompanying drawing, illustrating a preferred embodiment of theinvention, wherein:

The FIGURE is a diagrammatic representation of a fuel metering andpumping system for fuel injection apparatus including a manifold sensingdevice in accordance with the invention.

With particular reference to the figure of the drawing one embodiment ofthe present invention will now be disclosed.

The fuel metering and pumping system 10 illustrated in the figurecomprises the pumping apparatus .12 for pumping fuel to the fuelinjection nozzle 14 for injection into the internal combustion engine16. The fuel pumped to the nozzle '14 is metered by means of theadjustable abutment 18 in accordance with engine parameters, such asmanifold vacuum by the metering means 20. Metering means 20 includes themanifold vacuum sensing device 22 which in accordance with the inventionis provided with means 24 for compensating for the effect of valveoverlap on manifold vacuum at idle engine speeds.

More specifically the pumping means 12 comprises a housing 26 includingan inlet conduit 28 from a source of fuel under pressure (not shown) andoutlet conduits 30 and 32. for alternately feeding fuel to fuelinjection nozzles associated with the engine 16. Pumping means 12further includes the bearing sleeve 34 secured within housing 26, therotatable metering sleeve 36 and the metering shuttle 38 movable betweenthe adjustable abutment 18 and a fixed abutment 40' in reciprocalpumping strokes.

The bearing sleeve 34 is provided with the openings 42 and 44 extendingtransversely therethrough. Openings 42 and '44 connect'at one end withthe passages 46 and 48 respectively. Passages 46 and 4 -8 leadrespectively to the outlet conduits 30 and 62 of the pumping means 12.Openings 42 and 44 connect at the other end with a longitudinallyextending recess 50. Recess 50 is in communication with inlet conduit28.

Metering sleeve 36 is provided with restricted openings 5-2 and 54therein which on rotation of sleeve 36 alternatively connect the inletconduit 28 to the interior of conduit 36 at opposite ends of shuttle 3'8through recess 50 and passages 42 or 44.

Thus in operation of the pumping means 12 as the sleeve 36' is rotatedthe fuel under pressure in conduit 28 will cause reciprocal movement ofthe shuttle valve 38 between the abutments 18 and 40 to alternately pumpa metered amount of fuel through conduits 30' and 32. The pumping strokeof shuttle valve 38 and thus the amount of fuel pumped per stroke isdetermined by the initial positioning of the fixed abutment 40' and theposition of the movable abutment 18 which is adjusted in accordance withengine parameters by fuel metering means Zll.

For a more complete explanation of the functioning of the pumping means.12 reference is made to U.S.

Patents Nos. 2,965,090 and 2,965,092.

The fuel metering means 26 includes the carriage 56 having the inclinedsurface 58 thereon engageable with the end 60 of the movable abutment 18. The inclination of the surface 58 of the carriage 56 is determined bythe position of the lever 62 which is rotatable about a pivot mounting63 in accordance with particular engine parameters, such as thecondition of operation of the engine 16 and the temperature thereof asis also more fully set forth in the United States patents referred topreviously.

The transverse position of the carriage 56 is determined by movement ofcarriage 56 in accordance with the manifold vacuum of the engine 16 bythe manifold vacuum sensing device 22 to which the carriage 56 isconnected by link 64 through pivot connection 66. It will be understoodthat both the transverse position of the carriage 56 and the inclinationof the surface 58 of carriage 56 will cooperate to determine the axialposition of the adjustable abutment l8 and therefore the fuel metered tothe combustion engine 16 on each stroke of shuttle 38.

The manifold sensing device 22 comprises the cylinder as having an endcover 68 Which end cover is secured to the body member 26 by convenientmeans, such as screws 70. A piston 72 is mounted for reciprocationwithin the cylinder 66 and is urged to the [right by means of the spring74 as shown in the figure. The cylinder 66 is connected to the intakemanifold '76 of the engine d6 by means of conduit 78 as illustrated.Thus the piston 72 is positioned axially of the cylinder 66 inaccordance with engine manifold vacuum to transversely position thecarriage 56 in a manner previously known during operation of the engine16.

Such operation has however been found to improperly meter fuel to theengine 16 when, the engine 16 has an increased valve overlap provided asrequired due to greater air flows and higher compression ratios inmodern engines. That is to say, with large high compression modernengines, for proper engine operation both the inlet and exhaust valvesof the engine are opened for a sufiicient length of time so that exhaustpressures are felt in the engine manifold at idle speeds. Thus if thefuel metered to such engines is adjusted for manifold vacuum atidlespeeds the fuel will be excessively rich for speeds above idle speeds.

Therefore the means 24 for compensating for valve overlap at idle speedsin these engines is provided. Compensating means 24 comprises thecylinder 34?: within piston 72 and the piston 82 [reciprocally mountedin cylinder 86. The bias spring 84 biasing the piston 82 to the right incylinder 80 as illustrated is also part of compensating means 24.

The piston $2 is pivotally connected by pivot means 86 directly to link64. The transverse position of the carriage 56 is therefore determinedby the position of the piston 82 Within the cylinder 80 as well as bythe position of the piston '72 in the cylinder 66.

Cylinder Si is connected to the manifold side of the carburetorinduction passage 90 at a point 92 just below the throttle valve gethrough the conduit 96, the radially extending passage 98 and the axialrecess M in the piston '72.

It will therefore be apparent that manifold vacuum will be felt incylinder 8d only when throttle valve 9% is positioned to place orifice92 on the manifold side thereof.

' Thus in operation at idle speeds before the throttle valve 94 isrotated counterclockwise toward an open position the adjustment of thetransverse position of carriage 56 is accomplished both by thecompensating means 24 and the usual manifold vacuum responsive piston72. At this time full manifold vacuum is present in cylinders 66 and 8tacting against springs 74 and 84 to move pistons 72 and 52 into aleftward limiting position as shown in the figure to move carriage 56 sothat it positions abutment 18 for proper metering of fuel at idle enginespeeds.

As the throttle valve 94 is rotated in a counterclockwise direction toincrease the speed of the engine the vacuum present in cylinder Sil willgradually be reduced to the vacuum on the venturi side of the throttlevalve 94 due to gradual movement of the adjacent edge of throttle valve94 past orifice 92 on the initial counterclockwise rotation of throttlevalve 94 from the closed position thereof. During this reduction invacuum in cylinder 80 the spring 84 gradually moves piston 82 to itsrightward limiting position in cylinder 80". Thus after the initialcounterclockwise movement of the throttle j valve 94 the compensatingmeans 24 is ineffective to position carriage 56 and control of thetransverse position of carriage 56 is accomplished in the usual mannerby means of piston '72, which is still under the influence of manifoldvacuum as felt in cylinder 66.

The effect of the compensating means 24 on the position of the carriageS6 at idle speeds may be adjusted by means of the adjusting screw 102iand spring 184 threaded in the passage 1% in carburetor housing 108. Thescrew M2 includes a valve end 11% for regulating the opening of theorifice 112 on the venturi side of the closed throttle valve 94 which isconnected by passage 114 to the conduit 96. Thus the vacuum in cylinder66 and the position of piston 82 and carriage 56 at idle engine speedmay be controlled by screw 102 to provide desired compensation fordifferent engines or engine operating conditions to insure optimum fuelmetering at both idle engine speeds and above even with the increasedvalve overlap required in large high compression modern engines.

The drawings and the foregoing specification constitute a description ofthe improved manifold sensing device in such full, clear, concise andexact terms as to enable any person skilled in the art to practice theinvention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

l. A fuel pumping and metering system for an internal combustion enginehaving an intake manifold comprising pumping means for delivering fuelto the engine, metering means operably associated with the pumping meansfor metering the fuel pumped by the pumping means in accordance with theposition of the metering means, positioning means comprising a cylinderin communication with the engine manifold and a piston mounted in saidcylinder for movement therein in accordance with manifold vacuum, andcompensating means connecting the metering means to the piston formovement therewith comprising a second cylinder formed in said piston, asecond piston mounted in the second cylinder and connected to themetering means, and means connecting the second cylinder to the enginemanifold at engine idle speed.

2. Structure as claimed in claim 1 wherein the engine includes athrottle valve and the means connecting the second cylinder to theengine manifold comprises a conduit extending between the secondcylinder and engine manifold connected to the engine manifold at a pointadjacent the throttle valve which point is on the engine manifold sideof the throttle valve only when the throttle valve is in substantiallyengine idle position.

3. Structure as claimed in claim 2 wherein said compensating meansfurther includes resilient means within the second cylinder and actingbetween the second cylinder and piston in opposition to manifold vacuumwhich resilient means is operable to gradually move the second piston toa limiting position with respect to the first piston on movement of thethrottle valve away from the engine idle position thereof to positionthe point at which the conduit between the second'cylinder and enginemanifold is connected to the engine manifold on the venturi side of thethrottle valve.

4. A fuel pumping and metering system for an internal combustion enginehaving an intake manifold comprising pumping means for delivering fuelto the engine, metering means operably associated with the pumping meansfor metering the fuel pumped by the pumping means in accordance with theposition of the metering means, positioning means comprising a cylinderin communication with the engine manifold and a piston mounted in saidcylinder for movement therein in accordance with manifold vacuum, andcompensating means connecting the metering means to the piston formovement therewith comprising a second cylinder formed in said piston, asecond piston mounted in the second cylinder and connected to themetering means and means connecting the second cylinder to the enginemanifold at engine idle speed, and

means for regulating the effect of the compensating means on saidmetering means.

5. Structure as claimed in claim 4 wherein the engine includes athrottle valve and the means connecting the second cylinder to theengine manifold comprises a vacuum conduit extending between the secondcylinder and engine manifold connected to the engine manifold at a pointadjacent the throttle valve which point is on the engine manifold sideof the throttle valve only when the throttle valve is in substantiallyengine idle position.

6. Structure as claimed in claim 5 wherein the means for regulating thecompensating means effect on said metering means comprises a passageconnecting the conduit between the second cylinder and enm'ne manifoldto the venturi side of the throttle valve and valve means for adjustingthe eifective size of the passage.

7. A fuel pumping and metering system for an in ternal combustionengine, comprising pumping means for delivering fuel to the engine,metering means opena'bly associated with the pumping means for meteringthe fuel pumped by the pumping means in accordance with the position ofthe metering'means, a cylinder, a piston mounted in said cylinder andconnected to said metering means for moving said mete-ring means inresponse to an engine parameter, a second cylinder, a second pistonmounted in said second cylinder and connected to the metering means formoving the metering means in response to an engine parameter only atpredetermined engine speeds.

7 determined engine speed is idle engine speed.

11. A fuel pumping and metering system for an internal combustion enginehaving an intake manifold comprising pumping means for delivering fuelto the engine, metering means operably associated with the pumping meansfor metering the fuel pumped by the pumping means in accordance with theposition of the metering means, positioning means mechanically connecteditO the metering means and directly responsive to manifold vacuum at allengine speeds for positioning the'metering means, and separatecompensating means directly rnechanically connected to the meteringmeans and responsive to manifold vacuum for further positioning themetering means in accordance with manifold vacuum at engine idle speed.i

12. Structure as set "forth in claim 11 wherein the separatecompensating means is carried by and movable with respect to thepositioning means.

References Cited in the file of this patent UNITED STATES PATENTS2,943,616 Boyer et al. July 5, 1960 2,954,018

Dermond Sept. 27, 1960-

1. A FUEL PUMPING AND METERING SYSTEM FOR AN INTERNAL COMBUSTION ENGINEHAVING AN INTAKE MANIFOLD COMPRISING PUMPING MEANS FOR DELIVERING FUELTO THE ENGINE, METERING MEANS OPERABLY ASSOCIATED WITH THE PUMPING MEANSFOR METERING THE FUEL PUMPED BY THE PUMPING MEANS IN ACCORDANCE WITH THEPOSITION OF THE METERING MEANS, POSITIONING MEANS COMPRISING A CYLINDERIN COMMUNICATION WITH THE ENGINE MANIFOLD AND A PISTON MOUNTED IN SAIDCYLINDER FOR MOVEMENT THEREIN IN ACCORDANCE WITH MANIFOLD VACUUM, ANDCOMPENSATING MEANS CONNECTING THE METERING MEANS TO THE PISTON FORMOVEMENT THEREWITH COMPRISING A SECOND CYLINDER FORMED IN SAID PISTON, ASECOND PISTON MOUNTED IN THE SECOND CYLINDER AND CONNECTED TO THEMETERING MEANS, AND MEANS CONNECTING THE SECOND CYLINDER TO THE ENGINEMANIFOLD AT ENGINE IDLE SPEED.